Device for holding precious stones



A. J. BENJAMINS.

DEVICE FOR HOLD ING PRECIOUS STONES.

APPLICATION FILED JAN. 10, 1920.

1,371,840. Patented Mar. 15, 1921.

j ASSER J. BENJAMITNS, or BROOKLYN, new YORK.

, DEVICE FOR HOLDING PRECIOUS STONES.

Specification of Letters Patent.

Patented Mar. 15, 1921 Application filed January 10, 1920. Serial' No. 350,520.

To all whom it may concern:

Be it known that I, Assnn J. ,BnNJAMINs,

a citizen of the United States, and a resident of Brooklyn, borough of Brooklyn,- county and State of New York, have invented a new and Improved Device for Holding Precious Stones, of which the following isa full, clear, and exact description. 7

This invention relates to an apparatus used in connection with the cutting of precious stones and has particular reference -to a device for holding precious stones.

The invention contemplates'and has for.

its principal object the provision of a device for holding stoneswi'th which a gage for determining the correct axle of the facets may be used without the necessity of removing the same therefrom.

Another object of the invention is to materially improve devices of this character in order to render the task of properly cutting and gaging the stone comparatively simple in comparison with methodsnow employed.

A further object of the invention is to provide an improved holding and retaining means for a stone which will accommodate gems of various sizes without thenecessity of changing the equipment and which provides means with which a suitable gage may be engaged to obtain the proper angularity of the bottom facets.

With the above recited and other objects in view, some of which will be more appar ent hereafter, reference is made to the following detailed description, the appended claims and accompanying drawings forming a part of this application, in which:

Figure 1 illustrates a side elevation of standard and Well-known appurtenances used in thediamond cutting art, and to which the device constituting this invention is applied.

Fig. 2 illustrates'a cross sectional view taken through a chuck or clamp used for holding a diamond in position while op-' erated on by a cutting wheel.

Fig. 3 shows a diamond holder constructed in two parts drawn to show the parts.

in separate relation.

Flg. 4 illustrates an ad ustable protractor of well-known design shown in service position, during the act of measuring the angle on the facet of a stone.

In presenting a more detail description of the invention there is shown in the drawlonger end to tightly fit into a socket of a;

chuck. The upper end of this shank is like wise tapered to fit into a socket 11 made in the cup 10. The socket 11 is made the counter-part of the shorter tapered end-of the shank 9 so that the cup may be tightly thrust and anchored in position on the top, end of the shank to form a stone holder 910. The cup 10 ismade to retain the diamond while a device as laterexplained, is used to clamp this diamond in the cup. The cup is made in the form of a cylinder, and has a peripheral rim 12. A sector of the rim 12 is removed to form a notch or opening in the cup to more readily expose the facet of the diamond on the side of the cup in which the notch is made. The rim 12 pro-- jecting above'the topface of the cup leaves a plane face 14 which acts as a base to seat the stone in position while being ground. The-table or face 14 is formed on aplane right angular with the axis of the cup and shank so that a stone clamped in position in the cup-and properly seated therein, with no dust 'or'grit particles between the stone and cup, occupies a correct position rela:

tively to the stone holder 910.

In the Figs. 1,2 and .tthere is shown a stone, such as a diamond 18, clamped into position within the cup'lO of the stone holder. A cup 10 has been selected in accordance with the diametral size of the girdle and top facet of the diamond. The stone '18 is then clamped into position with the table and top facet placed in contact with the face 14 and rim 12 of the cup. This maintains the aXis of the stone 18 coincident with the axis of the stone holder so that the stone occupies a po sition relatively correctrto-the stone holder. 7 The stone holder 9-10 is mounted in a diamond cutters' chuck 19 by thrusting the shank 9 into a socket made in the chuck for the-reception of thetapered shank; The '1 stem 22 is iixedin the chuck to mount it in a vise arm 23 on the diamond cutters worktable to receive the chuck andhold it in serv-.

ice position relatively to the grinding and polishing wheel 24:.

As is well known to those skilled in the.

art, the bezels, corners and pavilions are cut on the face of the diamond by holding the diamond against the grinding wheel 24k and accurately cutting the diamond until the proper angularity is obtained. every separate corner and pavilion on the face must be individually ground; therefore it necessitates a great deal of measuring to determine when the proper angle has been reached.

An adjustable protractorcomprises a protractor blade 26 pivotally mountedin a protractor frame 27. The frame has the clamp screw 28 which tightens the frame on the protractor blade 26 to maintain the correct setting of the instrument. The inner end 29 of the'protractor frame 27 is vertically true so that it may be applied against the outer cylindricalface of the diamond holding cup 10. The outer surface edge of the protractor blade 26 then becomes alined with the facet of the stone, and if the plane edge of the protractor is coincident with the plane of the facet the diamond cutting mechanic then knows that the facet being measured is accurately ground and the stone is remounted in the cup for the next cutting operation.

Fig. 4 shows the manner of applying the protractor against the stone holding cup 10 and the diamond 18. The plane vertical end 2 29 of the protractor is placed against the cup and the line indicating the protractor edge lies coincident with the line indicating the facet of the diamond. It is seen therefore that thediamond 18 in Fi 5 is ground accurately, as far as the 'angiilarity of the particular facet being-ground is concerned.

l is obtained.

The stone is then returned to the grinding wheeland a little more of the stone is carefully ground away until the correct angle- In taking measurements, the diamond cutter usually lifts thechuck 19 and vise from the wheel in. order to getsufiicient light on Each and the device. It is nevernecessary for a mechanic to remove the stone 18 from the cup for thereason that thediamond cup used in combination with the protractor may be brought togetherjto effect the desired measurements. This particular accomplishment and faculty of the appurtenance constituting this invention makes for economy and efficiency in practising. the art.

Having thus described my invention, I desire to secure by LettersPatent:

1. In a device of the character described, means for supporting a stone from a chuck for cutting the bottom facets thereof, said means including a hat base to receive the table facet ofthe stone and a right angularly disposed wall affording a base with which-a protractor gageis adaptedto co-act for gaging the proper uniform angularity ofithe bottom facets without the necessity of removing the stone therefrom.

2. In a device of: the character described, a stone receiving member having a flat outer end wall and an outerside wall disposed at right angles to said'endlwall', and means for retaining the table facet; of the stone in operative contact withv the end wall, the said side walls constituting a. base with which.

1 jecting from said end wall, as and for the lar side wall, an annular flange on said: end. wall having an open.s1de,the said end wall and means clamping the table facet of the stone against said end, wall, the said side wall;

affording a. base with which a protractor gage. may co-act to obtain the proper uniform angularity of the bottom facets without the necessity of removing the stone therefrom.

asses J. BENJAM NsQ 

